在同一个表上触发INSERT和UPDATE

as all of us know, entity framework can't hold geography data. So my idea was, to specify the longitude and latitude as decimal in my model. After executing the SQL script for creating the tables I would start another script for adding a geography column. Then I would like to update this column on every INSERT or UPDATE (on longitude and latitude) by a trigger. Is the following trigger okay, or is it something bad? I'm asking because I'm not very familiar with trigger, but it works for now.as all of us know, entity framework can't hold